I am curious about how people handle their coffee cup. I just wipe mine out once in a while. I find that soap in a seasoned coffee cup is like running into a day hiker after being in the woods for a week. Both seem like a good thing, but I react with a "man that was gross" every time I run into such a thing. The day hiker smells like they took a bath in 50 perfumes and the coffee tastes like it was made with 50% soap.
Non hikers are about a psi shy of a legal ball.